auto-filling top-off resevoir
 

Hey, hopefully somone can help out.

I've been trying for a while to find plans for an auto-top off resevoir I saw a while ago. It's designed to hold 5 gallons, and has a divider and an airline check valve that makes it fill only when it's empty. It's designed to prevent TDS creep.

anyone seen the thread? I'm trying to remember how it was built and can't.

Even better, anyone have any other good suggestions to prevent TDS creep when hooking an RO/DI straight to the tank?

Is this what you're talking about?

That's cool, I've never seen that before. I'm going to try one.
I haven't really had a problem with TDS creep cuz of the DI after the R/O but it's tough on the resin.

cool..

great site!

no much simpler and WAY cheaper. I remembered how to make it. Now I need to figure out if I can run a 50' hose from my ro/di to my tank, or if that's too long of a run. Then I'll be looking for a float switch...

here's a diagram. it's not my design, I just couldn't find the thread I found it, can't even remember which site:

http://www.kwirky88.com/images/aquarium/resevoir.gif

you need something to construct it out of (acrylic or glass), a means to drill whatever material you choose, a float switch, and an air valve.

When it's filling, air can escape through the air valve. when it's full, the float switch will turn the RO unit off.

when it starts to drain, the large chamber is emptied only, because the air valve keeps the small chamber full, UNTIL the bottom is reached, where it fills it back up again.

you just do the math, and make it whichever size you want to hold.

still sourcing cheap float switches that are meant to be installed THROUGH aquarium glass (usually drilled with a 5/8" bit).

Hmmm interesting. I seem to remember reading this too, just can't place when and where.

I'm tempted to try this with some of the scrap acrylic I've got. Please post back if you find an appropriate float switch.

Wait ... Does it have to be a float switch? Why couldn't a float valve work?

I have done this topping off directly into the sump useing a furnace humidifier float switch.

This might been the thread http://216.187.96.54/vbulletin/showthread.php?t=27193&page=1&highlight=float

Still have my ro/di direct to float in the sump. After more than a year of running my unit with no maintenance (yes, I over used the filters and resins) highest I seen my TDS was 20. Changed filters and resins back to low TDS.

btw, just went downstairs and ran a few oz into a cup from the float, got a TDS of 5.

Mark, your link seems to be broken...